#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define mod 1000000007
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
int n;
vector<int> v,a,b;
vector<vector<int>> dp;
int f(int pos,int q,int w){
if(q < 0) return 2037;
if(pos >= n) return 0;
if(dp[pos][q] != 2037) return dp[pos][q];
dp[pos][q] = min(f(a[pos],q,w) + 1,f(b[pos],q-1,w));
return dp[pos][q];
}
void solve(){
int p,q;
cin >> n >> p >> q;
v.assign(n,0),a.assign(n,0),b.assign(n,0);
for(int i=0;i<n;i++){
cin >> v[i];
}
if(p + q >= n){
cout << 1 << endl;
return;
}
auto check = [&](int m){
dp.assign(n,vector<int>(q+1,2037));
for(int i=0;i<n;i++){
a[i] = lower_bound(all(v), v[i] + m) - v.begin();
b[i] = lower_bound(all(v), v[i] + 2*m) - v.begin();
}
return f(0,q,m) <= p;
};
sort(all(v));
int l = 1,r = 1e9;
while(l < r){
int m = (l + r) / 2;
if(check(m)) r = m;
else l = m + 1;
}
cout << l << endl;
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
